Combined coil and coil form with integral conductive legs



E. STANWYCK Oct. 13, 1964 COMBINED COIL. AND COIL FORM WITH INTEGRAL CONDUCTIVE LEGS Filed April 5. 1960 ATTORNEYS United States Patent 3,153,213 COMBINED COIL AND CDIL F ORM WITH INTEGRAL CONDUCTKVE LEGS Edmund Stanwycir, RJ). 4, Box 404, Newburgh, NY.

. Filed Apr. 5, 1960, Ser. No. 20,692

7 Claims. (Cl. 336-192) This invention relates in general to new and useful improvements in electronic components and the method of making the same, and more particularly relates to a novel coil form having integral conductive legs and the method of making such a coil form.

Coil forms are presently in the form of elongated tubes of paper board, plastic and other suitable non-conductive materials. The necessary coil is wound onto the coil form and the terminal ends of the coils, when in use, are connected to other electronic components. When the coils are used in conjunction with printed circuits or it is other- I wise desired to simply mount the coils, the coil forms are provided with legs, certain of which may be terminals. This is particularly true when the coil is used in conjunction with a printed circuit wherein the legs of the coil form may come into direct contact with circuit portions of the printed circuit board when they are plugged thereinto. At the present time, coil form terminals are in the form of elongated legs which are suitably secured to one end of the coil form preferably by means of small tabs or prongs projecting through the coil form and being upset on the inner surface thereof. These legs are normally provided in elongated strip form and in a single operation on a complicated and highly precision machine the strip material is first shaped into the desired configuration and is then appliedin a continuous operation. It will be readily apparent that the coil form must be properly indexed between each leg applying operation. While this arrangement has proved satisfactory, it is, of course, desirable, to provide a more satisfactory method of providing coil forms with conductive legs. It is to this end that the present invention relates.

In accordance with the invention, it is a primary object to provide a coil form which has legs integral therewith, and the legs. being provided with a conductive material wherein coil forms with conductive legs may be rapidly produced at a minimum of cost. 7

Another object of the invention is to provide a coil form wherein the lower portion thereof is in the form of integral projecting legs, and wherein each leg is provided with a metallic coating, such as copper or other similar metal having good conductor properties, wherein the legs of the coil form may serve to both support the coil form and to provide electrical terminals for coils secured thereupon.

Still another object of the invention is to provide a novel method of forming coil forms having integral conductive legs, the method including the initial shaping of a coil form to have integral projecting legs, and then applying to the legs, preferably on the exterior surfaces thereof, a metallic coating wherein the metal of the coating has good electrical conductive properties.

A further object of the invention is to provide a novel.

method of forming a coil form having integral conductive .legs,fwherein a conventional'leng'th of coil form tubing is first providedwith a collar of metal having good electrical conductive properties, which collar may besecured on the tube by means of a cement or the like, after which the lower end of the tube from which the coil form is being shaped is cut to provide integral depending legs, the cut extending completely through the metal collar so that the depending legs are provided with metal layers which are spaced and insulated from each other.

Still another object of the invention is to provide a novel method of providing a coil form which has inte- 3,153,2l3 Patented Oct. 13, 1964 ice gral conductive legs, the method including the providing of a coil form having integral depending legs, applying a suitable ink to the surfaces of the legs, which ink is of a conventional nature and over which plating of metals, such as copper, may be accomplished, and then applying a metal coating overthe ink by a plating process so that each of the legs, or those legs which are to be conductors, may be provided with a metal conductive coating.

With the above, and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims, and the several views illustrated in the accompanying drawing.

In the drawing:

FIGURE 1 is a fragmentary exploded perspective view showing a coil formed in accordance with the invention ready for plugging into a printed circuit board on which other electronic components have been mounted.

FIGURE 2 is a developed view of a coil form blank for the purpose of showing the arrangement of the legs depending from the coil form. I

FIGURE 3 is a perspective view of a coil form blank having integral depending legs.

FIGURE 4 is a perspective View of the blank of FIG- URE 3, after an ink over which metal may be plated has been applied to thesurfaces of the legs.

FIGURE 5 is a perspective view of the coil form blank of FIGURE 3 after the completion thereof by the coating of conductive metal over the ink on the legs.

FIGURE 6 is an enlarged fragmentary vertical sectional view, taken along the line 6-ti of FIGURE 5, and shows the specific details of one of the legs of the coil form and the conductive metal coating thereon.

FIGURE 7 is a perspective view of a blank to be used in another method of forming a coil form in accordance with the invention.

FIGURE 8 is a perspective view of the blank of FIG- URE 7 after a collar of conductive metal has been secured to the lower end thereof.

FIGURE 9 is a perspective view of the finished coil form with portions of the lower end thereof cut away to define separate spaced legs having metal coatings thereon, the coatings being formed from the collar.

FIGURE 10 is an enlarged fragmentary vertical sectional View, taken along the line lit-ill of FIGURE 9, and shows the specific details of the leg construction of the coil form of FIGURE 9.

Referringnow to the drawings in detail, it will be seen that there is illustrated in FIGURE 1 a typical printed circuit board Ill on which electronic components 7 l2 and 13 have been mounted. The form of printed cricuit board 11 illustrated has printed circuitry 14 on the underside thereof and is provided with eyelets l5 forthe reception of mounting legs or prongs- It is to be understood that the printed circuit board it illustrated is only one or the many printed circuit boards which are available, and the printed circuitry 14 may just as well be on the upper surface thereof as on the underside thereof, and the eyelets or grommets 15 may be eliminated for purposes of simplicity, when desired.

Associated with the printed circuit board ii. for plugging into the grommets 15 is a coil, generally referred to by the numeral 16, and constructed in accordance with the invention. The coil 16 includes a coil form, generally referred to by the numeral 17, on which two windings 18 and 19 are positioned. it is to be understood, of course, that the coil 16 may be formed of one or more windings, and not necessarily two, as illustrated, and that, when desired, other electronic components, such as resistors, may be incorporated in the coil construction.

As is best shown in the developed View of FIGURE 3 2, the coil form 17 includes a body 2i) having a plurality of legs 21 depending therefrom. The legs 21 are spaced circumferentially about the lower portion of the body 20 and are integrally connected thereto. However, it is to be understood that the spacing of the legs 21 may vary so that they day be utilized for indexing purposes. This is clearly shown in FIGURE 2.

The coil form 117 may be produced by several methods, two of which are outlined below.

In the first of these methods, the coil form 17 is formed by first providing a blank 22 which has the body 20 and the legs 21 of the final coil form 1'7 of their desired shape. The blank 22 may be molded from plastic, either in its final shape or in the form of a tube with the legs 21 defined by cutting material therefrom, or from paperboard in the form of a tube cut to the desired length and with the legs 21 defined by cutting away portions of the paperboard tube. 01? course, as stated above, other materials may be used for the construction of the coil form.

The first operation performed on the blank 22 is the application of ink 23, such as by dipping, to the surfaces of each of the legs 21, with the ink terminating short of the body 20 so that the ink applied to the legs 21 is not coextensive. The ink 23 is a conventional commercially available ink which is characterized by the fact that a metal, such as copper, may be plated directly thereover irrespective of the base material.

The blank 22 next passes through a plating process wherein a conductive metal coating 24 is applied over the ink coating 23. It will thus be apparent that the legs 21 of the final coil form 17 have conductive metallic coatings thereon, which coatings extend entirely about the legs 21. It is preferred that these coatings be copper, although silver and other conductive metals may be utilized.

Referring now to FIGURES 7 through 10, inclusive, it will be seen that there are disclosed the steps in the forming of the coil form 17 by another method. In following the second method, a blank 25 is provided. The blank 25 is formed of plastic, paperboard or similar materials and is in the form of a short length of tubing.

A collar or band 26 is telescoped over and is suitably secured to the lower portion of the blank 25 by means of a suitable adhesive. The blank is then cut away along the lower portion thereof to define the individual legs 21, the legs 21 extending above the metal coating 26 of the collar so that the metal on the individual legs is not electrically connected. It is to be understood that the blank 25 is initially of the proper height so that once the legs 21 have been formed, the remainder of the blank 25 defines the body 2% and the resultant structure is the desired coil form 17.

When the coil form 17 is formed through the placing of collar or band 26 on the blank 25, each and every leg will have a metal coating 26. On the other hand, when the coil form 17 is formed from the blank 22, it is not necessary that each of the legs 21 have a metal coating 24 thereon, although, for ease of manufacture, it may be desirable to coat each leg 21.

The legs 21 have been illustrated as being elongated and of constant width. However, it will be readily apparent that the legs 21 may have pointed lower ends to facilitate the placing of the legs 21 in openings in the printed circuit board 11. Also, if desired, the legs 21 may be of a lesser width at the bottom thereof than at the upper portion thereof, so that the lower edge of the body 20 may be spaced above the surface of the printed circuit board for insulating and cooling purposes.

Reference is again made to FIGURE 1, wherein it is shown that terminal portions of the windings 13 and 19 [l are secured to the metal coatings on the legs 21, the metal coatings being, for example, the metal coatings 24. The securement of the terminal portions of the windings 18, 19 will be accomplished by the application of a solder drop 27, for example.

When the coil 16 is positioned on the printed circuit board 11, the legs 21, in passing through the printed circuit board 11, firmly position the coil 16 thereon. When grommets 15 are provided, the desired electrical connection may be accomplished by the frictional engagement of the metallic coatings 24 or 26 with the grommets. On the other hand, when the grommets are not used, or even when the grommets are used, the electrical connections may be assured by the application of solder or other conductive bonding materials.

From the foregoing, it will be seen that the novel and advantageous provision has been made for carrying out the desired end. However, attention is again directed to the fact that variations may be made in the example methods and coil form structures disclosed herein without departing from the spirit and scope of the invention, as defined in the appended claims.

I claim:

1. A coil form comprising a generally cylindrical body having a circular cross-section and consisting of insulating material around which a winding may be disposed, said cylindrical body having a plurality of depending legs, said legs being integrally connected to said cylindrical body and extending longitudinally from an end of the cylindrical body, and each of said legs having an electrically conductive coating on at least one surface thereof.

2. The coil form of claim 1 wherein said electrically conductive coating is formed of metal.

3. The coil form of claim 1 wherein said electrically conductive coating is formed of metal plating.

4. The coil form of claim 1 wherein said electrically conductive coating is formed of a metal layer, and an adhesive secures said metal layer to a respective leg.

5. The coil form of claim 1 wherein the cylindrical body is of a continuous construction.

6. The coil form of claim 1 wherein the conductive coating on each leg extends entirely thereabout.

7. An. electrical coil comprising a generally cylindrical tubular body formed of insulating material, a plurality of legs integral with said cylindrical tubular body and formed of the same insulating material and extending longitudinally from an end of the cylindrical body, a coating of conductive material on each one of at least a pair of said legs, an electrical winding wrapped around said cylindrical tubular body and having a pair of terminal portions, one of said pair of terminal portions being connected to one of said pair of legs, and the other of said pair of terminal portions being connected to the other of said pair of legs.

References Cited in the file of this patent UNITED STATES PATENTS 2,667,624 Bels Jan. 26, 1954 2,707,272 Blitz Apr. 26, 1955 2,762,113 Daniels et al. Sept. 11, 1956 2,762,987 Mackey Sept. 11, 1956 2,816,252 Sanders Dec. 10, 1957 2,816,253 Blitz Dec. 10, 1957 2,922,138 Comins Jan. 19, 1960 2,925,646 Walsh Feb. 23, 1960 OTHER REFERENCES Publication: Bang Edge Dip-Soldering of Printed Circuits, Tole-Tech and Electronic Industries, December 1955, pages 74, 75, 146 and 149. 

1. A COIL FORM COMPRISING A GENERALLY CYLINDRICAL BODY HAVING A CIRCULAR CROSS-SECTION AND CONSISTING OF INSULATING MATERIAL AROUND WHICH A WINDING MAY BE DISPOSED, SAID CYLINDRICAL BODY HAVING A PLURALITY OF DEPENDING LEGS, SAID LEGS BEING INTEGRALLY CONNECTED TO SAID CYLINDRICAL BODY AND EXTENDING LONGITUDINALLY FROM AN END OF THE CYLINDRICAL BODY, AND EACH OF SAID LEGS HAVING AN ELECTRICALLY CONDUCTIVE COATING ON AT LEAST ONE SURFACE THEREOF. 